A three phase type of investigation is planned oriented toward developing a fuller understanding of organic brain syndrome (OBS) in the elderly as it is reflected in their behavioral, biological and medical functioning. The specific aims are as follows: (1) Determining the relationships among behavioral, biomedical and environmental variables of groups of elderly individuals: (a) those who are free of OBS; (b) those with mild, (c) moderate, and (d) severe OBS. (2) Improve the diagnostic process in assessing the biological and behavioral assets and liabilities of aged individuals - with particular reference to the use of new diagnostic techniques (CT scan, evoked potentials, and neuropsychological tests) and the adaptation of others to the specific characteristics and needs of the elderly. (3) Study the natural course of changes in functioning of elderly persons with OBS over a 12-month period in comparison with individuals found to be free of OBS. (4) Determination of the mediating effect of social support systems and of environmental supports and demands on such elderly Ss in relation to change over time in psychosocial functioning; (5) Determination of effectiveness of two kinds of followup procedures with such Ss following the comprehensive diagnostic evaluation - one which offers only recommendations and one which offers regular guidance during a 12-month period for carrying out the recommendations. The three phases thus involve: (1) a cross-sectional study; (2) a longitudinal study over a 12-month period; and (3) an evaluation of intervention study.